RIVERVIEW — There were days in years past when water flowing by homes on the Alafia River more closely resembled cafe con leche than an inviting place for people to swim and fish.

Seagrasses in Hillsborough Bay near the mouth of the river were nearly nonexistent when the Tampa Bay Estuary Program began monitoring such things in 1990.

Farming, phosphate mining, wildlife waste and natural levels of nitrogen from phosphate in Florida waters all have contributed to the Alafia River's designation as an “impaired” water body. It is one of several rivers that flows directly into Tampa Bay.

The state recently approved a basin management plan that includes 78 projects meant to stem the tide of pollution running into the Alafia River and, eventually, Tampa Bay.

Some of the projects have been completed, and results are palpable.

“Clarity comes and goes, depending on the time of year,” said Sybil Cribbs, who has operated Alafia River Canoe Rentals in Valrico for 38 years. “When we moved here in the 1970s, we would go to bed and the water would be relatively clear. We would wake up with it looking like coffee with a lot of cream in it. We don't see that anymore. Whatever they have done to stop that is helping.”

Farther south, where the river flows into Hillsborough Bay near Gibsonton, seagrasses are coming back. In fact, said Tampa Bay Estuary Program director Holly Greening, Hillsborough Bay is seeing the largest percentage of seagrass growth of any area in Tampa Bay.

There is no quick fix, but progress is showing, said Terry Hansen, a professional geologist with Florida's Department of Environmental Protection. “We look to limit and reduce current and future activities so water bodies can be restored.”

The basin plan is connected to federally mandated criteria that delineate how much pollution a water body can handle and still function successfully. Before reaching an agreement last year, the state and the U.S. Environmental Protection Agency disagreed about what those pollution limits should be.

The federal water quality criteria are meant to protect aquatic life, and people's health, in estuaries and coastal waters from nitrogen and phosphorus pollution.

The Mosaic Co. is a major partner in the basin plan and has undertaken many projects to filter its phosphate mining runoff before it reaches tributaries of the Alafia, said company spokeswoman Martha Monfried. With some projects complete, she said, the company has reduced by 75 percent the amount of nitrogen it discharges into the Alafia.

Too much nitrogen and phosphorus in water can cause algae blooms, which harm water quality and habitat, say EPA officials who oversee the nation's Clean Water Act. Those blooms decrease oxygen in the water that fish and other aquatic life need to survive.

“If you put sugar in iced tea, it only takes so much before it quits dissolving,” Hansen said. It's the same with nutrients in water. “It's really difficult to answer in terms of how bad it is” in the Alafia River, Hansen said. “All we can say is that it is low-level impairment.”

Mosaic, one of the state's largest phosphate producers, since 2003 has been buying land and building wetlands to filter its runoff and taking other measures to improve the quality of water coming from its operations, Monfried said,

Tampa Bay Water — the region's potable water provider — Hillsborough County government and Tampa Electric Co. all have projects either completed or in the works to improve the quality of stormwater runoff flowing from their properties into the Alafia.

And the state's Department of Agriculture is working with farmers to implement practices that will reduce the amount of water they use, the stormwater runoff they create and the amounts of fertilizer used on strawberries, other row crops and trees, Hansen said.

Six areas of the Alafia are targeted by the basin plan: the mouth of the river, Turkey Creek, Mustang Ranch Creek, English Creek, 30-mile Creek and Poley Creek.

“We are now finding that levels are dropping, particularly nutrient levels causing the dissolved oxygen issues,” Hansen said. “The actions already underway are bearing fruit. You can't just throw a switch and change the levels coming out of a plant.”

The projects will take time, he said.

A collaboration among the state, the estuary program and other entities is the best way to approach water quality issues, Greening said. The estuary program developed the Tampa Bay Nitrogen Management Consortium a few years ago to address pollution issues in Tampa Bay, and this basin plan grew out of that. “Overall, the recovery of Tampa Bay has shown how successful a collaborative approach can be,” she said.

A similar management plan has been approved to address fecal coliform in the Hillsborough River, and work is underway to develop a plan to address nutrients in that river, said Department of Environmental Protection spokeswoman Ana Gibbs.

Fecal coliform is a bacterial indicator of contamination by fecal matter of humans or animals.

The department recently approved a basin plan for the Manatee River in Manatee County.